diff --git a/Makefile b/Makefile
index 498c569..8b9c95a 100644
--- a/Makefile
+++ b/Makefile
@@ -2485,12 +2485,16 @@ ifeq ($(CONFIG_RTL8723B), y)
 $(MODULE_NAME)-$(CONFIG_MP_INCLUDED)+= core/rtw_bt_mp.o
 endif
 
-obj-$(CONFIG_RTL8821CU) := $(MODULE_NAME).o
+# export CONFIG_RTL8821CU=y to build driver in tree
+# else driver will be built out of tree by default
+ifeq ($(CONFIG_RTL8821CU), y)
+	obj-y := $(MODULE_NAME).o
+else
+	obj-m := $(MODULE_NAME).o
+endif
 
 else
 
-export CONFIG_RTL8821CU = m
-
 all: modules
 
 modules: